<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <div>
            <p>请选择你要购买的书籍</p>
            <ul>
                <li v-for="(item,index) in arr">
                   {{item.name}} <button @click=" item.count++ ">买书</button>
                </li>
            </ul>
            <table border="1" width="500" cellspacing="0"> 
                <tr>
                    <th>序号</th>
                    <th>书名</th>
                    <th>单价</th>
                    <th>数量</th>
                    <th>合计</th>
                </tr>
                <tr v-for="(item,index) in arr">
                    <th>{{index + 1}}</th>
                    <th>{{item.name}}</th>
                    <th>{{item.price}}</th>
                    <th>{{item.count}}</th>
                    <th>{{item.price * item.count}}</th>
                </tr>
            </table>
            <p>总价格为:{{totalPrice}} </p>
        </div>
    </div>
    <script src="./vue.js"></script>
    <script>
        const app = new Vue({
            el: '#app',
            computed:{
                totalPrice() {
                    const total = this.arr.reduce(( sum, item) => {
                        return sum + item.price * item.count
                    } ,0)
                    return total

                }
            },
            data: {
                arr: [
                    {
                        name: "水浒传",
                        price: 107,
                        count: 0,
                    },
                    {
                        name: "西游记",
                        price: 192,
                        count: 0,
                    },
                    {
                        name: "三国演义",
                        price: 219,
                        count: 0,
                    },
                    {
                        name: "红楼梦",
                        price: 178,
                        count: 0,
                    },
                ],
            },
        
        })
    </script>

</body>

</html>